McDonald's has a problem with Christmas, and the holidays generally. It's not that McD's is against the festive season. Rather, it's that McDonald's can't really compete against the giant turkey and ham dinners that bookend the final month of the year.

So McDonald's must engage in some clever counter-programing, and that's one of the reasons the McRib sandwich tends to get rolled out across its franchises in Q4 — and then removed again a few weeks later.

This year, the McRib is planned for a four- to six-week period in the latter half of Q4, according to DDB Chicago CEO Peter McGuinness, whose ad agency is creating a campaign to promote it. DDB is McD's lead ad agency, and McGuinness is thus the chain's top outside adman.

We asked him why, if the McRib is so popular, doesn't McDonald's just add it to the menu permanently?

Turns out that not that many people actually like the McRib. Or rather, McDonald's is so huge that it needs all its items to be massively popular in order to keep their place on the menu. Those who do like the McRib, love it. But in the broader scheme, "It's not a mass play year-round," McGuinness says.

Thus McD's deploys the McRib strategically, when the calendar leaves the company without a natural hook for its products — like at Christmas time. "We don't really do polar bears," McGuinness says.

Instead, the McRib functions as "a great piece of buzzy news that surprises and delights, late in the year on the marketing calendar."

Of course, news is only news if it's new, and for the McRib to be "new" it must disappear again for the rest of the year once its Q4 revenue marketing duties are done. (A bit like Santa Claus himself.)